The present invention relates to a process for creating a conducting plasma channel for igniting an arc in an environment with reduced pressure by means of high voltage.
Such a process is known from WO-8,503,954. This patent publication discloses a new process for the ignition of an arc which, in contrast to the process known from U.S. Pat. No. 3,783,231 and U.S. Pat. No. 3,836,451 makes use of non-mechanical means for igniting an arc. This has the advantage that the device can be made smaller and is more reliable because of the absence of moving parts. This ignition described in WO-8,503,954 is called plasma-electronic ignition of the arc. In order to make this ignition possible, the anode and the cathode must be close together, while the optimum pressure must be higher than that which is usual for the deposition of metals in vacuum. This process has, however, a number of disadvantages. Due to the fact that the cathode and the anode are close to each other, deposition of material gives rise to the risk of the cathode and anode being short-circuited. In addition, the chamber containing the cathode and anode together with the substrate must be placed under a higher pressure during the ignition of the arc, after which the pressure has to be reduced again in order to allow the vacuum deposition on the substrate to proceed in optimum conditions.
The object of the present invention is to avoid these disadvantages.